Method for fabricating organic nanocomposite

A method of making a zeolite USY/carboxylated cellulose nanocomposite, comprising:

• grinding date-palm tree leaflets to form ground date-palm tree leaflets;
• adding NaNO2 stepwise to a mixture comprising ground date-palm tree leaflets and HNO3 to form a first reaction mixture;
• stirring the first reaction mixture at 80 to 90° C. for 8 to 12 hours;
• adding distilled water to the first reaction mixture to form a quenched mixture;
• washing the quenched mixture with distilled water;
• centrifuging the quenched mixture to collect carboxylated cellulose nanofibers;
• equilibrating the carboxylated cellulose nanofibers in distilled water to form equilibrated carboxylated cellulose nanofibers;
• wet ball milling zeolite USY to form wet ground zeolite USY;
• rinsing wet ground zeolite USY with distilled water and centrifuging to collect a milled zeolite USY;
• drying the milled zeolite USY at 60° C. to 100° C. for 60 to 120 min to form a dried zeolite USY;
• crushing the dried zeolite USY to form crushed zeolite USY nanoparticles;
• mixing triethylamine with a dispersion comprising crushed zeolite USY nanoparticles and carboxylated cellulose nanofibers to form a second reaction mixture;
• autoclaving the second reaction mixture at 60° C. to 80° C. for 15 to 30 hours, cooling, and centrifuging to collect a wet product;
• and
• drying the wet product at 50° C. to 80° C. for 15 to 30 hours to form the zeolite USY/carboxylated cellulose nanocomposite.